How do I prevent this Google Analytics C# DotNetOpenAuth ProtocolException? - google-api

Question

I'm using the Google APIs for .NET. I'm following the example project Simple OAuth2 but I keep getting a Protocol Exception from DotNetOpenAuth.
Here's what I have now:
public static void Main( string[] args )
{
// Register the authenticator.
NativeApplicationClient provider = new NativeApplicationClient(
GoogleAuthenticationServer.Description, gaAppId, gaSecret );
OAuth2Authenticator<NativeApplicationClient> auth = new OAuth2Authenticator<NativeApplicationClient>(
provider, GetAuthorization );
AnalyticsService analyticsService =
new AnalyticsService( new BaseClientService.Initializer {
Authenticator = auth,
ApplicationName = #"Test Application",
} );
DataResource.GaResource.GetRequest request = analyticsService.Data.Ga.Get(
gaId, #"2013-09-04", #"2013-09-18", "ga:totalEvents" );
GaData data = request.Execute();
Console.ReadKey();
}
private static IAuthorizationState GetAuthorization( NativeApplicationClient arg )
{
// Get the auth URL:
IAuthorizationState state =
new AuthorizationState( new[] {AnalyticsService.Scopes.AnalyticsReadonly.GetStringValue()} );
state.Callback = new Uri( NativeApplicationClient.OutOfBandCallbackUrl );
// Retrieve the access token by using the authorization code:
return arg.ProcessUserAuthorization( authCode, state );
}
Notes:
I'm using the Analytics API in this code because that's what I need. I get the same error when using the Tasks API as described in the sample.
The authentication code is a refresher token generated by the process as defined in the example code. The error comes in both cases (request a new token, or re-use an old one.)
The ProtocolException that is triggered by DotNetOpenAuth is there because accounts.google.com returns an error: invalid request.
Here's what the OAuth request looks like:
Aplication/x-www-form-urlencoded; charset=utf-8
User-Agent: DotNetOpenAuth/4.3.1.13153
Host: accounts.google.com
Cache-Control: no-store,no-cache
Pragma: no-cache
Content-Length: 148
Connection: Keep-Alive
code=REDACTED&redirect_uri=urn%3Aietf%3Awg%3Aoauth%3A2.0%3Aoob&grant_type=authorization_code
And this is what the Google returns:
HTTP/1.1 400 Bad Request
IRRELEVANT_HEADERS
{
"error" : "invalid_request"
}
I'm at a bit of a loss here as to why this happend and how I can solve this. I can't find any other working C# examples. It seems to be a different kind of error than the one in this thread. Is there any of you who knows how I can fix this?

Answer 1

I studied the examples provided by peleyal some more and managed to find the issue. The problem was that I wasn't actually storing a refresh-token, I was storing an authentication token. I should've used the authentication token to generate the refresh token.
Here's the full solution in a simplified manner for future reference. The differences can be found in the GetAuthorization function, which now correctly saves the refresh token and opens a browser window to request the authorization when a refresh token is not yet available.
private static refreshToken = null;
public static void Main( string[] args )
{
// Register the authenticator.
NativeApplicationClient provider = new NativeApplicationClient(
GoogleAuthenticationServer.Description, gaAppId, gaSecret );
OAuth2Authenticator<NativeApplicationClient> auth = new OAuth2Authenticator<NativeApplicationClient>(
provider, GetAuthorization );
AnalyticsService analyticsService = new AnalyticsService( new BaseClientService.Initializer {
Authenticator = auth,
ApplicationName = #"Test Application",
} );
DataResource.GaResource.GetRequest request = analyticsService.Data.Ga.Get( gaId, #"2013-09-04",
#"2013-09-18", #"ga:totalEvents" );
GaData data = request.Execute();
Console.ReadKey();
}
private static IAuthorizationState GetAuthorization( NativeApplicationClient arg )
{
// Get the auth URL:
IAuthorizationState state = new AuthorizationState(
new[] {AnalyticsService.Scopes.AnalyticsReadonly.GetStringValue()} );
state.Callback = new Uri( NativeApplicationClient.OutOfBandCallbackUrl );
if( !string.IsNullOrEmpty( refreshToken ) ) {
try {
state.RefreshToken = refreshToken;
arg.RefreshToken( state );
} catch {
refreshToken = null;
}
}
// If the refresh token is empty, request a new one by opening
// a browser window. Allows the user to paste its authorization token
// and saves the refresh token.
if( string.IsNullOrEmpty( refreshToken ) ) {
Uri authUri = arg.RequestUserAuthorization( state );
// Request authorization from the user (by opening a browser window):
Process.Start( authUri.ToString() );
Console.Write( " Authorization Code: " );
string authCode = Console.ReadLine();
Console.WriteLine();
// Retrieve the access token by using the authorization code:
state = arg.ProcessUserAuthorization( authCode, state );
refreshToken = state.RefreshToken;
}
return state;
}